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- Author or Editor: Laura J. Armbrust x
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Abstract
Objective—To identify common errors in film and digital radiographs provided by referring veterinarians and determine the effect of such errors on the perceived diagnostic quality of image sets.
Design—Prospective study.
Sample—135 sets of radiographic images acquired by referring veterinarians for client-owned small animals evaluated at a university hospital.
Procedures—Sets of radiographs were prospectively collected and evaluated for proper performance of various radiographic technical variables including exposure, collimation, positioning, inclusion of all appropriate views, presence of artifacts, radiation safety, and labeling. Sets of radiographs were subjectively determined to be of diagnostic or nondiagnostic quality by 2 evaluators.
Results—The variables exposure, correct positioning, absence of artifacts, and acquisition of all appropriate views were significantly associated with a determination of diagnostic quality for radiograph sets. Correct patient labeling, radiation safety, and x-ray beam centering and collimation were not associated with a determination of diagnostic quality for radiograph sets. The number of categories with errors was significantly associated with identification of radiograph sets as having diagnostic or nondiagnostic quality. Digital radiographs had a significantly lower number of image artifacts and significantly higher frequency of proper labeling versus film radiographs.
Conclusions and Clinical Relevance—Results of this study suggested the technical variables proper exposure, proper positioning, absence of artifacts, and acquisition of all appropriate views were important for acquisition of sets of radiographs of high diagnostic quality. Identification of these errors and adjustment of radiographic technique to eliminate such errors would aid veterinarians in obtaining radiographs of high diagnostic quality and may reduce misinterpretation.
Abstract
Objective—To compare the detection of pulmonary nodules by use of 3-view thoracic radiography and CT in dogs with confirmed neoplasia.
Design—Prospective case series.
Animals—33 dogs of various breeds.
Procedures—3 interpreters independently evaluated 3-view thoracic radiography images. The location and size of pulmonary nodules were recorded. Computed tomographic scans of the thorax were obtained and evaluated by a single interpreter. The location, size, margin, internal architecture, and density of pulmonary nodules were recorded. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for thoracic radiography (with CT as the gold standard).
Results—21 of 33 (64%) dogs had pulmonary nodules or masses detected on CT. Of the dogs that had positive CT findings, 17 of 21 (81 %) had pulmonary nodules or masses detected on radiographs by at least 1 interpreter. Sensitivity of radiography ranged from 71 % to 95%, and specificity ranged from 67% to 92%. Radiography had a positive predictive value of 83% to 94% and a negative predictive value of 65% to 89%. The 4 dogs that were negative for nodules on thoracic radiography but positive on CT were all large-breed to giant-breed dogs with osteosarcoma.
Conclusions and Clinical Relevance—CT was more sensitive than radiography for detection of pulmonary nodules. This was particularly evident in large-breed to giant-breed dogs. Thoracic CT is recommended in large-breed to giant-breed dogs with osteosarcoma if the detection of pulmonary nodules will change treatment.
Abstract
Objective—To determine correlation between results of computed tomography (CT) versus pathologic examination for determining the volume percentage of affected lung in mice experimentally infected with Pasteurella pneumotropica.
Animals—30 adult mice.
Procedure—After helical CT scans on day 0, mice were inoculated intranasally with P pneumotropica. Repeat CT scans were performed on days 1, 2, 3, 4, 6, 8, 10, and 13. Regions of interest (affected areas) were manually drawn on the CT images, and percentage volume of normal lung was calculated by use of 3 methods: first-day volume, largest volume, and last-day volume. Three mice were euthanatized for pathologic evaluation after each scan day. The lungs were examined with a dissection microscope, and lesion scores were assigned on the basis of percentage volume of pneumonia. Correlation coefficients comparing results of the 3 CT methods with results of gross examination were calculated.
Results—Lung abnormalities were detected via dissection microscopy by postinfection day 2 and via CT by days 2 or 3. Correlation coefficients for the 3 CT methods of analysis, compared with pathologic findings, were 0.7 via first-day lung volume, 0.8 via largest lung volume, and 0.8 via last-day lung volume.
Conclusions and Clinical Relevance—Results of CT correlated well with results of dissection microscopy for estimating percentage volume of lung affected by pneumonia in mice experimentally infected with P pneumotropica. This method may be useful for longitudinal studies of pneumonia in mice. (Am J Vet Res 2005;66:835–838)
